Discharging hopper for grain dryer

ABSTRACT

A grain dryer has imperforate side and end walls, two horizontal grain supports, and a series of exhaust ducts above the upper grain support. Each grain support has valve means to transfer periodically a controlled amount of grain downwardly from the upper to the lower grain support and from the lower grain support to a discharge means. A blower supplies hot air which passes up through the upper grain support to heat the bed of grain supported thereby, and cool air which passes through both grain supports. Level responsive means maintains a free space beneath the upper grain support. The two valve means operate only when the air supply is cut off.

United States Patent Mathews Sept. 3, 1974 DISCHARGING HOPPER FOR GRAIN DRYER Inventor: Bernard C. Mathews, PO. Box 70,

Crystal Lake, Ill. 60014 Filed: July 9, 1973 Appl. No.: 377,391

US. Cl 214/17 D, 34/168, 222/245, 222/276, 222/459 Int. Cl. B65g 65/44, F26b 17/26 Field of Search 222/243, 245, 276, 275, 222/459; 214/17 D; 34/165, 168

References Cited UNITED STATES PATENTS 2/1939 Hubmann et a1... 34/168 X 5/1948 Yglesias-Paz 222/459 UX 6/1953 Reed 34/165 3/1970 Flink 2l4/l7 D Primary ExaminerRobert B. Reeves Assistant Examiner-Frederick R. Handren Attorney, Agent, or Firm-Bayard Jones [57] ABSTRACT A grain dryer has imperforate side and end walls, two horizontal grain supports, and a series of exhaust ducts above the upper grain support. Each grain support has valve means to transfer periodically a controlled amount of grain downwardly from the upper to the lower grain support and from the lower grain support to a discharge means. A blower supplies hot air which passes up through the upper grain support to heat the bed of grain supported thereby, and cool air which passes through bothgrain supports. Level responsive means maintains a free space beneath the upper grain support. The two valve means operate only when they air supply is cut off.

2 Claims, 10 Drawing Figures PATENTED SEP 31974 DISCHARGING HOPPER FOR GRAIN DRYER This invention relates to an enclosed type, grain dryer in which the movement of the grain is intermittent.

In many continuous flow enclosed type grain dryers the air is supplied to the grain through open bottomed ducts. The grain in the space above the ducts tends to move in columns with the result that some grains remain in this space much longer than other grains. If this space is a heating zone, as where the air from the ductsv moves upwardly, then some grains would be dried longer than others, resulting in a non-uniform product.

According to my invention, I provide two or more beds or conditioning zones and provide for an intermittent free falling movement of the grain from one bed'to the other so that the grains will become randomly mixed during the free falling motion. Also, the rate of discharge is sufficiently great as to avoid any columnar differentiation in a bed or zone.

Another objection to a continuous flow dryer is that the continual movement of the grains in the presence of air stream loosens or abrades the chaff and beeswings so that these fines are blown out of the dryer by the air stream, providing air pollution.

According to my invention, the air stream is shut off during the transferring movement of the grainwith the result that the chaff and other particles move with the grain step by step from the point of introduction into the dryer to the point of discharge. During periods in overlying same. More specifically, it permits upward passage of large air volumes, such as 100 cubic feetper minute per square foot of bed area while the grain is being supported, and it includes valve means which permits very rapid free falling movement through the support in controlled quantities.

Other objects, features and advantages will become apparent as the description proceeds.

In the drawings:

FIG. 1 is a longitudinal vertical section of a preferred embodiment of my invention;

FIG. 2 is a vertical transverse section taken along line 2-2 of FIG. 1;

FIG. 3 is a vertical longitudinal section of the combined grain support and transfer device, with portions omitted for purpose of clarity;

FIG. 4 is a section taken along line 44 of FIG. 3;

FIG. 5 is a transverse section taken along. line 5-5 of FIG. 3;

FIG. 6 is a view showing the drive means at one end of the pusher 70 shown in FIG. 3;

FIG. 7 is a detailed section taken along line 7-7 of FIG. 2 showing the air lock at the left-hand end of the apparatus shown in FIG. 1;

FIG. 8 is a section taken along line 8-8 of FIG. 7;

FIG. 9 is a diagram showing the operating-cycle; and

FIG. 10 is a block diagram showingthe operating and control means for the various elements of the dryer.

As shown in FIGS. 1 and 2, the dryer comprises a casing 10 having grain feed means 11 at the top and grain discharge means 12 at the bottom, as well as suitable support means, not shown.

A grain support 13 is located above the grain discharge means. Air supply means including a blower 14 supplies air to the space 15 beneath the grain support 13. As shown in FIG. 1, there is a bed 16 of grain overlying the grain support 13, the top level of which is indicated by the reference numeral 17.

A second grain support 18 is located above the grain bed 16 so that a free space l9'is provided beneath the grain support. The blower 14 also supplies air to the free space 19. Exhaust ducts 20 are located above the grain support 18 which are effective to prevent any substantial amount of air from passing above the ducts. These extend transversely of the casing 10 and through the side walls 22 so that all air supplied by the supply means 14 is exhausted to the atmosphere.

There is a bed 23 of grain overlying the grain support 18, the top level of which is above the ducts 20.

A movable door 25 is provided in one of the end walls 26 to control the passage of air from the blower- 14 to the space 15 beneath the grain support 1 3.

A similar door 27 is provided between space l9 and blower 14. A duct 28 leads from fan 14 to the two doors 25, 27 and means are provided to operatethe doors alternately so that air first goes through just the bed 23 into the ducts 20, and then through both beds 16 and 23 into the ducts 20.

Each grain support 13 and 18 comprises a series of stationary plates 30 disposed side by side transversely of the casing 10and spaced from each other to provide slots 31 therebetween. Stationary covers 32 overlie the slots 31, and in the arrangement shown, comprise angular plates located on approximately 10 inch centers, providing a series of hoppers which direct the grain down onto the plates 30.

A pusher assembly 33, shown in FIGS. 3 and 5, comprises side rails 34 which ride on rollers 35 joumalled in supports 220 on the side walls 22 of the casing. The side rails support a series of push bars 37, one for each stationary plate 30, which overlie the same. The pusher assembly 33 is reciprocated by a crank 39-connected to the pusher assembly by a link 38.

As shown in FIG. 3, each cover 32 carries at each side thereof a bracket 40 for supporting a pin 41. For each half of each cover, there are threesuch brackets and pins, one located near either end, and one in the middle. A baffle 42 extends the full width of the casing and is connected to the three pins 41 by three connecting members 43. The connecting member has an elongate opening 44 as shown in FIG. 4-so that-it loosely fits over the pin 41 and can rock about the point 4'5.- Thus,

the lower edge of the baffle 42 will move aboutankarcuate path, the center 45 of which is laterally-displaced. away from said lower baffle edge so that the verticalcomponent of baffle motion will be accentuated.

The object of this arrangement is to provide a relatively large opening or throat 46 between the lower edge of the cover 32 and the surface of the-plate 30' so thata substantial quantity of grain can be displaced laterally by the push bar 37 toward and downwardly throughthe slot 31. However, theprovision of a throat 46 of substantial vertical dimension, in order to facilitate rapid transfer of grain, will cause the grain to flow over the edge of the plate 30 and into the slot even when the push bar 37 is stationary in its centered position shown in FIG. 3. Therefore, the baffles 42 are provided to prevent lateral movement of the grain when the parts are in the grain support position of FIG. 3. The slots 31 are of sufficient width to permit a large volume of air to pass upwardly through the grain bed 16 or 23, and in this connection, the spacing of the baffles 42 with respect to the covers 32 provides a passageway 47 (FIG. 4) of substantial width so that the provision of the baffles does not offer any substantial resistance to the air flow.

The grain supports 13 and 18 thus permit the upward passage of air, and also when the pusher assembly 33 is reciprocated, they cause grain to be transferred downwardly through the slots 31.

In operation, the apparatus provides a heating zone H and a cooling zone C for the grain. Since the air from the blower 14 does not pass above the ducts 20, the heating zone I-I comprises only the space between the grain support 18 and the ducts 20.

The cooling zone C comprises the bed 16 which overlies the grain support 13 and which is of a limited depth.

The blower 14 operates in alternating stages of heating and cooling. I

In the embodiment shown, the zones H and C are each about two feet deep. The grain is transferred from zone to zone in increments, such as six inches at a time. The driving means 39 operates the transfer mechanism only when the doors 25 and 27 are closed so that air does not traverse the moving and tumbling grain, and therefore the chaff and beeswings are not separated and blown out through the ducts 20.

By thus transferring the grain in increments, the grain is brought up to the maximum temperature in zone I-I gradually, the lowermost layer having been subjected to the hot air stream for the longest time and therefore being the hottest. Also, as the air moves up through the several layers, it gives up part or most of its heat so that the uppermost layer in zone H is not subjected to the shock of exceedingly hot air.

Similarly, in the cooling zone C, the lowermost layer is the coolest and the air takes on heat from the grain as it rises with the result that the uppermost and hottest layer is not subjected to the shock of cool air.

The heater 50 is located in the blower intake. During the heating stage, the door 27 is open and the door 25 is closed. At this time, the heater is operative. Thus high temperature air is supplied only to the bed of grain 23 which overlies grain support 18. At the termination of the heating stage, the door 27 is closed and the door 25 opens, initiating the cooling cycle during which the heater 50 is generally inoperative. During the cooling cycle, air from the blower l4 traverses both zones C and B. At the termination of the cooling stage, the grain supports 13 and 18 are operated so that a layer of cooled grain from bed 16 is transferred to the grain discharge 12, and a layer of hot grain from the bed 23 is transferred to bed 16.

It will be noted that during the heating stage, no air traverses the bed 16. This is utilized as a tempering period during which the internal and shell temperature of each grain tends to become equalized.

The cycle of operation is diagrammatically illustrated in FIG. 9. Starting with the 12 oclock position there is first the heating stage, then the cooling stage, which is followed by the grain transfer. The length of the cycle hour. The combined grain support and transfer device is effective to transfer six inches of grain in about thirty seconds, the pusher bars 37 being substantially 1 inch high.

In some instances, I have found that improved results are obtained by operating the heater 50 for the first portion of the cooling stage so that the air passing through the open door 25 and the bed 16 initially has a temperature of 150 F., after which the heater fuel is cutoff and the air temperature drops to ambient, as shown in FIG. 9.

The air temperature in the heating stage is preferably in the 200 F. to 250 F. range.

The block diagram of FIG. 10 shows the operating means for the doors 27, 25, the grain supports 13, I8, and for the fuel control valves 70, 71 for the heater 50. The doors 27, 25 are operated into open position by suitable electric motors 60, 61 respectively acting through worm gear drives (not shown). The grain supports 18, 13 are operated by electric motors 62, 63, respectively, which drive the cranks 39 (FIG. 6).

A cycle timer switch 64 comprising a continuously rotating contact arm 65 and stationary arcuate contacts 66 corresponding to the particular cycle of FIG. 9 controls the sequence of operation of electric motors 60 to 63. For variations in the particular cycle (other than the duration, which is controlled by regulating the speed of the motor, not shown, which drives the contact arm 65) the stationary contacts 66 are mounted on a removable board 67 so that a different set of contacts 66 representing a different relative timing can be substituted. In the alternative, a stepping relay and adjustable timers can be used as a control device which permits convenient variation in the cycle of operation.

The cycle timer switch 64 also controls the transfer operation of the grain supports 13 and 18 so that the grain supports will operate only when both doors 27, 25 are closed. However, the amount of grain transferred by the grain support 13, that is, from the bed 16 to the discharge means 12, is determined by a counter 68 operating off of the shaft of the crank 39. For example, twenty-five complete revolutions of the crank 39 may be effective to transfer six inches of grain, in which event the counter is set to open after the twenty-fifth revolution the circuit between the motor 62 and the corresponding contact 66a of the cycle timer switch 64.

A level responsive device 51 (FIG. 2) is connected between the contact 66a and the motor 63 and it controls the transfer operation of the grain support 18 to assure that the bed level 17 will be maintained. Thus the initiation and termination of the transfer operation of the grain support 18 is controlled by the level responsive device, an example of which is shown in Lau US. Pat. No. 3,210,493, granted Oct. 5, 1965.

The temperature of the heated air is controlled by regulating the amount of fuel supplied to the heater 50, one solenoid valve 70 being set to provide the high temperature, such as 250 F., and the other valve 71 being set to provide a much lower temperature, such as similar to switch E, where this type of operation is desired as pointed out above. Where ambient temperature is desired throughout the entire cooling stage, then the alternate fuel supply 71 is omitted. The operation of the solenoid valves 70, 71 is controlled by a cycle timer switch 72,

The blower 14 is preferably a backward-curved cen-.

trifugal type of blower which. is non-overloading, thus permitting control of the air supply means by the doors 25 and 27.

The side and end walls 22 and 26 of the casing are imperforate walls in the sense that the air from blower 14 does not pass through samll perforations therein but escapes to the atmosphere primarily through exhaust ducts, such as the exhaust ducts 20.

Although only a preferred embodiment of my invention has been shown and described herein, it will be understood that various modifications and changes can be made in the construction shown without departing from the spirit of my invention, as pointed out in the appended claims.

.11 claims.

1. A combined grain support and transfer device for an intermittent flow grain dryer comprising'a series of stationary plates disposed side by'side and spaced from each other to provide slots therebetween, cover members spaced above said stationary plates and overlying said slots, and each having an edgeportion overhanging said stationary plate and spaced therefrom to provide ;a throat for the passage of grain therethrough, push bars mounted for reciprocating motion above said stationary plates and beneath said cover members and movable between a plate centered position and a displaced position adjacent to one'of said slots, a pivotally mounted baffle located above one of said stationary plates and beneath an associated said cover member at a point close to the edge of said slot whereby movement of said push bar into'said displaced position will cause a controlled amount of grain to move through said throat and to engage said baffle and swing it away from said edge of said slot to permit said grain to move into said slot, said baffle normally blocking lateral movement of said grain through said throat and into said slot when said push bar is stationary in said plate centered position.

2. A combined grain support and transfer device as claimed in claim 1 in which said cover members comprise angle plates, means on the underside of said asso ciated angle plate and above the said edge portion thereof mounting said baffle and providing a pivot center therefor which is laterally offset away from said baffle in a direction toward said angle plate edge portion. 

1. A combined grain support and transfer device for an intermittent flow grain dryer comprising a series of stationary plates disposed side by side and spaced from each other to provide slots therebetween, cover members spaced above said stationary plates and overlying said slots, and each having an edge portion overhanging said stationary plate and spaced therefrom to provide a throat for the passage of grain therethrough, push bars mounted for reciprocating motion above said stationary plates and beneath said cover members and movable between a plate centered position and a displaced position adjacent to one of said slots, a pivotally mounted baffle located above one of said stationary plates and beneath an associated said cover member at a point close to the edge of said slot whereby movement of said push bar into said displaced position will cause a controlled amount of grain to move through said throat and to engage said baffle and swing it away from said edge of said slot to permit said grain to move into said slot, said baffle normally blocking lateral movement of said grain through said throat and into said slot when said push bar is stationary in said plate centered position.
 2. A combined grain support and transfer device as claimed in claim 1 in which said cover members comprise angle plates, means on the underside of said associated angle plate and above the said edge portion thereof mounting said baffle and providing a pivot center therefor which is laterally offset away from said baffle in a direction toward said angle plate edge portion. 